In this paper a 5^th order low-pass continuous time analog filter in CMOS 45nm technology is presented. The filter design is based on a single compact cell used to synthesize five poles. The circuit performs the low-pass filtering of the in-band signal, while the in-band thermal noise is high-pass filtered, improving Signal-To-Noise-Ratio. 1-GHz -3dB-bandwidth is obtained by a prototype of the filter simulated in 45nm CMOS technology node (also Process-Voltage-Temperature simulations are available). The overall power consumption is 9mW from a single 1.2V supply voltage. 54dB@THD>40dBc is the SNR at 0dB gain.